The superclouds of the local Milky Way

Vol. 706
5. Galactic structure, stellar clusters and populations

The superclouds of the local Milky Way

Superclouds are the largest structures identified so far in the interstellar medium. With typical sizes of a kiloparsec, superclouds have been identified through HI observations in external galaxies and the inner parts of the Milky Way, but their presence in the solar neighborhood has remained poorly constrained. To remedy this situation, Lilly Kormann and collaborators have investigated the large-scale organization of the local interstellar medium using 3D Gaia-based dust maps and found seven highly elongated and mostly parallel structures in the local 5 kpc^2. These structures resemble superclouds, and nearly all known star-forming regions in the solar neighborhood lie within one of them. This finding supports the idea that superclouds act as gas reservoirs for the formation of giant molecular clouds and therefore regulate cloud formation and star formation on Galactic scales.